US researchers have proposed a hybrid energy concept that they claim will be able to produce power around the clock by combining solar generation with hydrogen production and storage.
The so-called “Hydricity” concept, devised by a team from Purdue University, Illinois, uses solar concentrators to focus sunlight and superheat water to operate a series of electricity-generating steam turbines and reactors for splitting water into hydrogen and oxygen.
“In the round-the-clock process we produce hydrogen and electricity during daylight, store hydrogen and oxygen, and then when solar energy is not available we use hydrogen to produce electricity using a turbine-based hydrogen-power cycle,” explained Purdue’s Professor Mohit Tawarmalani.
The system – which is detailed in the Proceedings of the National Academy of Sciences – has so far just been simulated using models, but according to the team it could be far more efficient than many other energy storage systems.
“The overall sun-to-electricity efficiency of the hydricity process, averaged over a 24-hour cycle, is shown to approach 35 percent, which is nearly the efficiency attained by using the best photovoltaic cells along with batteries,” said Purdue researcher Emre Gençer. “Our proposed process stores energy thermo-chemically more efficiently than conventional energy-storage systems,” he added, “the coproduced hydrogen has alternate uses in the transportation-chemical-petrochemical industries, and unlike batteries, the stored energy does not discharge over time and the storage medium does not degrade with repeated uses.”
The so-called hydrogen economy has been in discussion for over 50 years. I recall the “Adam and Eve” project in the 1970s was to use hydrogen from nuclear power at night to provide a hydrogen cycle. The scheme proved as credible as the Adam and Eve in Genesis.
It seems that people have to re-learn periodically that hydrogen, despite being a fantastic thermodynamic gas in terms of specific heat, calorific value and potential power-cycle efficiency, is a very difficult gas to store and transport safely and must be at high pressure for most uses due to low density.
The recent proposal to convert Leeds to hydrogen to avoid carbon dioxide would put the entire population of Leeds under considerable risk. I would suggest converting the Palace of Westminster as the first demonstrator.